Thanks Captain for pointing out that link which led me to this link.
I was thinking something like that which is why I was really surprised that I still have not been able to get 3 Stars on my PzIB.
I think my problem has been suppressing the crap out of the enemy to allow the PzIB to finish off. This just does not garner that much exp and I cannot attack hard units because PzIb has no HA strength. I think I will hold back my PzIB on most scenario's and possibly bring him out for Stalingrad Docks and Stalingrad Ruins to take advantage of the lack of sight from the enemy to draw them into traps.
I know a PzIb with enemies having 4 extra Strength sounds crazy but with 2 to 3 arty back up makes for a great enemy trap.
Thoughts, and if anybody has a formula I would love to see it?